Guttenberg was named advisor to the EU's internet commissioner Neelie Kroes on Monday, with the particular remit of the role of the internet in authoritarian regimes in the Arab world.
But many German commentators noted that during one of his previous incarnations as economics and technology minister in 2009, Guttenberg had come out in favour of website blocks for child porn, despite expert advisers saying they were an ineffective instrument against paedophiles.
Others feared that government-imposed website blocks would set an uncomfortable precedent for internet freedoms.
Andrea Nahles, general secretary of the opposition Social Democratic Party (SPD), came up with the phrase that provided plenty of headlines in the German press when she described Monday's appointment as “putting the fox in charge of the henhouse.”
Guttenberg's relationship with internet freedom was also tested earlier this year when revelations on the crowd-sourced online platform Guttenberg Wiki uncovered wholesale plagiarism in his doctoral thesis. The scandal stripped him of both his doctorate and his ministerial post.
"Just this year, I was personally exposed to the power of the internet," Guttenberg joked about the affair at a press conference in Brussels on Monday. "And I recognize and value its capacity to draw people in power to account."
But internet activists, some of whom would theoretically be cooperating with Guttenberg in his new job, were less amused. Human Rights Watch described Kroes' initiative to promote internet freedom as good, but was “astonished” at her choice of personnel.
Frank Rieger, spokesman for the hackers' collective Chaos Computer Club, told the Welt newspaper, “We see no reason to meet with a deceitful braggart who can't even admit that he lied and plagiarized and is now presenting himself as the saviour of the internet.”
The internet itself was bursting with ridicule for Guttenberg on Tuesday. One German Twitter user compared the appointment to making Playboy founder Hugh Hefner an equality commissioner.
More drily, lawyer and IT specialist Christoph Kappes, noted on the Google + network, “He is a technology enthusiast with thorough knowledge of the manipulative technology that allows him to use weak points in the systems to his advantage.”
But maybe satirical German TV show “Extra 3” came up with the best joke. Next to a photoshopped picture of Guttenberg dressed as a member of the Pirate Party – the party whose central issue is internet freedom - the caption appeared, “Freedom for the internet! Copy and paste for all!”